Size Tunable Polymer Core-Shell Nanoparticles for Cisplatin Delivery to Cancer Cells

Abstract

In this work, we synthesized biodegradable and biocompatible di-block copolymers based on γ-substituted caprolactone and polyethylene glycol. The caprolactone monomer was ring opened by an initiator, polyethylene glycol monomethyl ether (Mw 2000 g/mol), in the presence of catalyst stannous(II) 2-ethylhexanoate (Sn(oct)2) to yield the polymer PEG2000-b-CPCLx. Seven polymers were synthesized by varying the number of substituted caprolactone units (the drug core) and keeping the polyethylene glycol shell the same. The polymers were characterized by 1H-NMR, 13C-NMR and Gel Permeation Chromatography (GPC) techniques. Thermo gravimetric analysis (TGA) and Differential Scanning Calorimeter (DSC) was used to study the thermal properties of the polymer. Upon characterization of these polymers, the side chain carboxylates in the polymer were stitched with the anti-cancer drug, cisplatin. The cisplatin-polymer conjugates were subjected to IR analysis. Dynamic light scattering (DLS) and Field Emission Scanning Electron Microscopy (FESEM) were used to characterize the self-assembled core-shell nanoparticles. Drug loading content (DLC) and drug loading efficiency (DLE) was estimated by TGA and by absorption spectroscopy (OPD assay). Following this, the stability of these particles in water and PBS buffer was studied. The aim is to understand the differences in therapeutic efficiency and DLC of these core variable, core-shell nanoparticles.